ammo related question

I have 70's High Standard Supermatic Citation. I've shot Winchester T22's in it - it seems to do fine. Yesterday, I tried some of the Aguila ammo from CMP - about every third round failed to fire. Looking through the spare parts that my father in law left (it's an inherited gun) I find that there is what seems to be a pretty complete rebuild kit. So What would be the most likely thing to do to get this gun shooting the Aguila ammo reliably? Should I replace the firing pin spring, firing pin, hammer spring, all of the above? I realize it simply may not shoot them well - period, but I'd like to try. Any and all responses accepted here.

If that is the case, your gun probably has the wrong recoil spring in it. The frames on these later Hi Std guns are fragile. The gun should have the right recoil spring in it and only shoot Std Vel ammo. Other ammos, like High and Hyper Velocity beat up the gun's frame and CAN cause the frame to crack.

In your case if a heavy spring is installed the beating moves from the rear of the frame to the face of the breech, both on the barrel and on the slide. I suggest you get the right spring in the gun (available at Brownells either as a 5.5 lb Hi Std spring or a Wolfe spring) and only shoot Std Vel ammo, like CCI STD VEL.

I give this advice to many that have Hi Std guns and many times hear back from sorry owners who did not heed my advice and broke the frame of their prized and expensive Hi Std gun. But you choose... its your gun.